BOSTON — A ban on the use of artificial trans fat in baked goods at bakeries in Boston took effect March 12 as part of the second phase of the city’s efforts to eliminate partially hydrogenated oil from foods and beverages, according to the Boston Public Health Commission (B.P.H.C).

Food service establishments in the city were required to stop using trans fats in September, but bakeries were given an additional six months to alter their menus.

With the ban, bakeries and food service establishments will no longer be allowed to use oils, shortening or margarines containing partially hydrogenated vegetable oil in the preparation of baked foods, deep fried dough and cake batter. The ban does not apply to food or beverages served in the manufacturer’s original sealed package or to products that contain less than 0.5 grams of trans fat per serving.

Establishments in violation of the ban will received a citation and be subject to a fine ranging from $100 to $1,000, according to the B.P.H.C. But companies found in violation will be allowed to appeal for an extension up to six months.

"There are no health benefits and no level of consumption of artificial trans fat that is considered safe," said Dr. Barbara Ferrer, executive director of the B.P.H.C. "In fact, public health research over the past 20 years has shown that trans fatty acids significantly contribute to heart disease and other health problems."

While Boston is the first city in Massachusetts to implement a ban on trans fats, other cities in the state are following suit. In addition, several states have either implemented similar measures or are considering them, including California, Hawaii, Illinois, Maryland, New York, Tennessee, Texas and, Washington as well as the District of Columbia.

The ban on trans fats come at a time when many cities and states are stepping up efforts to curb obesity and improve health and wellness efforts. In addition to trans fat legislation, many cities and states are considering regulations that would require restaurants to post nutrient information on menu boards.